You could try doing the equivalent operation directly with libvirt
(virsh vol-delete [...]). If that also crashes the machine, take a
look at any errors in log files under /var/log/libvirt.

> This occurs all the time, in Kde4 the crash sometime takes out the entire
> desktop (this doesn't occur in gnome3) leaving me with a black screen...
>
> On the server I can see apparmor messages - for example
>
> type=1400 audit(1321440182.218:74): apparmor="DENIED" operation="open"
> parent=1211 profile="" name="/dev/dm-5"
> pid=14653 comm="virt-aa-helper" requested_mask="r" denied_mask="r"
>
> Is this related ?
>
> Does anyone have any ideas how to stop the crashing ?